Alzheimer’s disease (AD) has been associated with cardiometabolic disorders such as obesity and diabetes. Does high sugar intake, which may lead to metabolic disorders, increase the risk of AD?
The study: This cohort study involved a retrospective analysis of 37,689 participants (average age of 62 years, 84% white) from the U.S. Women’s Health Initiative - Dietary Modification Trial (WHI-DM) that investigated the associations between sugar intake and AD risk. The WHI-DM consisted of a randomized controlled dietary modification trial held during 1993–2005 with annual survey follow-ups for long-term health outcomes until 2019.
Dietary data were collected using food frequency questionnaires at baseline and at year 1 and included six subtypes of sugar intake (fructose, glucose, galactose, lactose, sucrose, and maltose measured in grams per day).
The follow-up surveys asked the participants whether a doctor had told them that they have a certain disease or complication (e.g., dementia/Alzheimer’s disease or moderate/severe memory problems).
The results: The 25% of participants who consumed the greatest amount of sugar (147 grams/day) had a 19% increased risk of incident AD compared with the 25% of participants who consumed the least amount of sugar (96 grams/day). Approximately 12% (4,586 participants) of the total sample reported having incident AD.
Of the six subtypes of sugar, lactose was significantly associated with AD risk. An estimated increase of 10 grams/day in total sugar intake (about 2.5 teaspoons) was associated with an increase in AD risk of 1.3%. Participants with cardiometabolic disorders had a higher risk of AD than those without.
Several baseline participant characteristics (e.g., race, education, and lifestyle factors) were significantly different across the range of sugar intake.